TEST(WTF_Deque, MoveOnly)
{
Deque<MoveOnly> deque;
deque.append(MoveOnly(1));
deque.prepend(MoveOnly(0));
EXPECT_EQ(0U, deque.first().value());
EXPECT_EQ(1U, deque.last().value());
auto first = deque.takeFirst();
EXPECT_EQ(0U, first.value());
auto last = deque.takeLast();
EXPECT_EQ(1U, last.value());
}
RefPtr<UniqueIDBDatabaseTransaction> UniqueIDBDatabase::takeNextRunnableTransaction(bool& hadDeferredTransactions)
{
Deque<RefPtr<UniqueIDBDatabaseTransaction>> deferredTransactions;
RefPtr<UniqueIDBDatabaseTransaction> currentTransaction;
while (!m_pendingTransactions.isEmpty()) {
currentTransaction = m_pendingTransactions.takeFirst();
switch (currentTransaction->info().mode()) {
case IndexedDB::TransactionMode::ReadOnly:
// If there are any deferred transactions, the first one is a read-write transaction we need to unblock.
// Therefore, skip this read-only transaction if its scope overlaps with that read-write transaction.
if (!deferredTransactions.isEmpty()) {
ASSERT(deferredTransactions.first()->info().mode() == IndexedDB::TransactionMode::ReadWrite);
if (scopesOverlap(deferredTransactions.first()->objectStoreIdentifiers(), currentTransaction->objectStoreIdentifiers()))
deferredTransactions.append(WTF::move(currentTransaction));
}
break;
case IndexedDB::TransactionMode::ReadWrite:
// If this read-write transaction's scope overlaps with running transactions, it must be deferred.
if (scopesOverlap(m_objectStoreTransactionCounts, currentTransaction->objectStoreIdentifiers()))
deferredTransactions.append(WTF::move(currentTransaction));
break;
case IndexedDB::TransactionMode::VersionChange:
// Version change transactions should never be scheduled in the traditional manner.
RELEASE_ASSERT_NOT_REACHED();
}
// If we didn't defer the currentTransaction above, it can be run now.
if (currentTransaction)
break;
}
hadDeferredTransactions = !deferredTransactions.isEmpty();
if (!hadDeferredTransactions)
return WTF::move(currentTransaction);
// Prepend the deferred transactions back on the beginning of the deque for future scheduling passes.
while (!deferredTransactions.isEmpty())
m_pendingTransactions.prepend(deferredTransactions.takeLast());
return WTF::move(currentTransaction);
}
